Research On Cross-Layer Optimization In Heterogeneous Network

With the improvement of technologies and user needs, today’s wireless communication network is developing towards the direction of diversification, which prompts the coexistence of different network. Under such circumstances, the concept of heterogeneous network has been proposed. However, this also brings some new challenges to the industry, such as how to manage the wireless resources between different systems and how to provide high quality multimedia services to users. Recently, cross layer optimization becomes a prevalent method to further improve the performance of wireless network. Different from the traditional design, cross layer optimization allows the communication between non-adjacent layers, which makes it more adaptive to the characteristics of wireless network. Taking into consideration the features of heterogeneous network, this paper mainly research on two key technologies, including joint admission control and vertical handover and wireless video broadcasting oriented joint source-channel coding.In the respective of joint admission control and vertical handover, an algorithm for heterogeneous network consists of LTE and WCDMA is proposed based on cross-layer utility function. In order to verify its performance, a simulation platform is built to get some numerical results about throughput, interference and handover success rate. The results show that this method has a good effect on balancing the load, coordinating the interference and improving the total throughput of the network.In the respective of wireless video broadcasting oriented joint source-channel coding, a wireless video broadcast scheme called SoftCast is studied and implemented in a software platform, the relevant results prove that this cross-layer design between application layer and physical layer can avoid the cliff effect and improve the robustness against packet loss. Then some practical advices are offered by delving into the parameters of SoftCast’s encoder. At last, as the complement research to the utility of this wireless video scheme, some performance analysis and optimization is presented on the sleep mechanism of mobile devices.